Fuel control valve



March 13, 1962 F. .1. BYDALEK ETAL 3,024,312

FUEL CONTROL VALVE Filed Dec. 7, 1959 2 Sheets-Sheet 2 INVENTORS FLOYDJ. BYDALEK GERALD E. DIETZ RUSSELL B. MATTHEWS ga -4 2. W

ATTORNEY United States Patent Ofifice 31,24,812 Patented Mar. 13, 19623,024,812 FUEL CONTROL VALVE Floyd J. Bydalek and Gerald E. Dietz,Milwaukee, and Russell B. Matthews, Wauwatosa, Wis., assignors, by mesneassignments, to Penn Controls, Inc, Goshen, Ind, a corporation ofIndiana Filed Dec. 7, 1959, Ser. No. 857,720 11 Claims. (Cl. 137-624.11)

This invention relates to improvements in fuel control valves and moreparticularly to timer controlled valves for gas burning incinerators orthe like.

In the operation of any gaseous fuel burning incinerator there is aminimum period during which the refuse should be exposed to the burninggas in order to incinerate a given load without the generation ofobjectionable amounts of smoke and odor. Even though the user isadequately instructed as to the minimum time setting recommended by themanufacturer for a given incinerator, such instructions are oftendeliberately disregarded in order to economize on fuel, with the resultthat a smoke and odor nuisance is created for which users sometimeswrongfully blame the manufacturer.

It is a general object of the present invention to provide an improvedfuel control valve for gas burning incinerators or the like whichinsures complete combustion of the burnable refuse placed in theassociated incinerator, without the generation of objectionable amountsof smoke and odor.

Another object of the invention is to prow'de an improved fuel controlvalve having a predetermined minimum time cycle of operation duringwhich gas is permitted to flow therethrough to the associated burner.

A more specific object of the invention is to provide an improved timercontrolled fuel control valve which cannot be set to open position forretention therein by the timing mechanism unless said timing mechanismis set to or beyond a predetermined minimum setting, there being meansfor preventing intentional turndown of the timing mechanism to less thansaid predetermined ruinimum setting.

Other and further objects and advantages of the invention will becomeapparent as the description proceeds, reference being had to thedrawings accompanying and forming a part of this specification in which:

FIGURE 1 is a vertical sectional view of one form of the improved fuelcontrol valve, the latter being shown in closed or off position;

FIGURE 2 is a view similar to FIGURE 1 showing the knob and associatedmechanism depressed to effect opening of the valve prior to rotation ofthe knob efiecting setting of the timing mechanism;

FIGURE 3 is a plan view of the dial and knob of the timing mechanismshowing the knob in off position;

FIGURE 4 is a view similar to FIGURE 3 showing the knob at thepredetermined minimum setting which in the illustrated device is onehour;

FIGURE 5 is a fragmentary sectional plan view taken approximately alongthe line V-V of FIGURE 1; and

FIGURE 6 is a fragmentary sectional plan view taken approximately alongthe line VI-VI of FIGURE 1.

Referring more particularly to FIGURES 1 and 2 of the drawings, theillustrated fuel control valve assembly comprises a lower body part 10and a complementary upper body part 11 held in assembled relation, as byscrews 12. The body part 10 is provided with an inlet fuel passage 13threaded to receive a fuel supply conduit 14, and a fuel dischargepassage 15 threaded to receive a conduit 16 for connection to the burnerthe fuel supply to which is to be controlled. The inlet and dischargepassages 13 and 15, respectively, are separated by a partition 17 formedwith an opening 18 surrounded by a flat annular valve seat 19 (FIGURE2). The partition 17 defines a cylindrical chamber 20, and the body part10 is formed with a threaded opening coaxial with said chamber forreceipt of a plug 21 provided with a guiding pin 22. A valve member 23is positioned within the chamber 20 for cooperation with the valve seat19 and is provided with a tubular guide sleeve portion 24 surroundingthe guide pin 22 as shown. A helical compression spring 25 is interposedbetween the valve member 23 and the plug 21 and surrounds the guide pin22 and guide sleeve portion 24, biasing the valve member 23 toward theseat 19.

The lower body part 10 is formed with an opening 26 in its upper surfacecoaxial with the opening 18 and communicating with the latter as well aswith the outlet passage 15 as shown. The opening 26 is closed by theupper body part 11 through the intermediary of a gasket 27. The upperbody part 11 is formed with a transverse partition 28 forming the bottomwall of an upper cup-shaped portion and the top wall of a downwardlyfacing recess 29 in registration with the opening 26 of body part 10.The partition 28 is formed with an upwardly projecting axial boss 30which is axially bored to receive a shaft 31, said boss being formed atits upper end with a coaxial annular groove 32 for receiving a resilientO ring seal 33, the latter being retained in place by a suitableretaining washer 34 staked within a suitable coaxial recess formed inthe upper end of the boss 30. The shaft 31 is movable axially as well asrotatably, and when depressed, engages the valve member 23, moving thesame to open position as shown in FIGURE 2.

The shaft 31 extends upwardly through a timing mechanism showndiagrammatically at 35, and is operatively associated therewith as willhereinafter appear. The timing mechanism 35 is disposed within andaffixed to a cupshaped housing member 36 telescoped within the cupshaped upper end of the upper body part 11 as shown. A pin 37 is fixedto and depends from the casing member 36 and is axially slidablydisposed within a bore 38 formed in the body part 11. The coaction ofthe pin 37 with bore 38 permits axial movement of the casing member 36with the timer 35 and shaft 31, but prevents rotative movement of saidcasing member and timer. Telescoped over the upper end of the casingmember 36 is an inverted cupshaped casing member 39 having an enlargeddiameter lower end or skirt portion 40. As shown in FIGURE 3 casingmembers 36 and 39 are formed with cooperating vertical indentations 41and 42 preventing relative rotation therebetween. A helical compressionspring 43 surrounds the boss 30 and is interposed between the partition23 and the bottom wall of the casing member 36, said spring biasing thecasing members 36 and 39, as well as the timer mechanism 35 and shaft31, upwardly toward the position shown in FIGURE 1.

The upper casing member 39 is formed in its upper wall with a centralaperture having fixed therein a flanged bearing member 44. A sleeve 45is telescoped over the upper end of the shaft 31 and is pinned theretoby an elongated diametrically extending pin 46 shown most clearly inFIGURE 5, said pin being pressed into registering diametrical openingsin the sleeve 45 and shaft 31. Relatively rotatably mounted on thesleeve 45 is a cylindrical fitting 47 having an enlarged diameter lowerend portion penetrated by an axial bore 48. The fitting 47 has a reduceddiameter intermediate portion 49 journaled in the bearing 44 andterminates in an upwardly extending coaxial squared shaft portion 50.The terminal portion 50 carries a knob 51, and an annular dust seal 52,for example of foamed plastic, surrounds the portion 49 of the fitting47 between the knob 51 and the bearing 44 as shown. Because of thesquared configuration of the por- 3 tion 50 of the fitting 47, rotationof the knob 51 effects corresponding rotation of the fitting 47.

As shown most clearly in FIGURE 5, the lower portion of the fitting 47is formed with a cutaway sector 53 through which the pin 46 projects. Inthe illustrated form of the invention the sector 53 is approximately(90) ninety degrees in extent, the size of the sector 53 depending uponthe rninimum time setting desired for the device. As shown in FIGURES 1,2 and 5, the fitting 47 carries a radially projecting pin 54, and theouter end of the pin 46 carries a retainer sleeve 55, there being ahelical tension spring 56 connected at one end to said retainer sleeveand at the other end to the pin 54. As shown in FIGURE the spring 56biases the fitting 47, and thereby the knob 51, in a clockwise directionwith respect to the shaft 31 to maintain the relationship of saidfitting and shaft shown in FIGURE 5.

As shown in FIGURES 3 and 4, the upper wall of the casing member 39carries a dial plate 57 indicating the initial or off position of theknob 51 and bearing time setting indicia which in the illustratedembodiment indicates timer settings up to four hours. Means is providedfor preventing counterclockwise rotation of the knob 51 beyond itsinitial or off position, said means comprising a pin 58 pressed intosuitable registering openings in the bearing 44 and the upper wall ofthe casing member 39 and depending therefrom, said pin cooperating witha pin 59 fixed to and projecting radially from the fitting 47 as shown.

As shown in FIGURES l, 2 and 6, a circular control disc 60 is coaxiallydisposed within the recess 29 and is formed with .a central hub portion61 extending above said disc and a hub portion 62 depending therefrom.The shaft 31 is formed with a reduced diameter lower end portion forminga shoulder 63, the hubs 61 and 62 being axially bored to receive thelower end portion of said shaft. An E-ring 64 is snapped into a suitableannular groove formed in the shaft 31, said ring engaging the hub 62 andretaining the hub 61 in engagement with the shoulder 63 to preventsubstantial axial movement of the disc 60 with respect to the shaft 31.

As shown most clearly in FIGURE 6, the control disc 60 is formed with aradial slot or escapement portion 65. A pin 66 is pressed into asuitable aperture in the partition 28 of body part 11 and depends fromsaid partition, said pin being accommodated within the slot orescapement portion 65 of the disc 60 when the parts are in the offposition shown in FIGURE 1. The hub portion 62 of the disc 60 is formedwith a cutaway sector 67, and a pin 68 is fixed to and projects from theshaft 31 through said cutaway portion as shown. Sector 67 is preferablyof about the same angular extent as the cutaway sector 53 in the fitting47, said cutaway sectors and the cooperating radially extending pinsrespectively affording lostmotion connections between the shaft 31 andknob 51 and said shaft and the control disc 60. To prevent rotation ofthe disc 60 except by engagement of the pin 68 with one or the other endwalls 67a and 67b of the cutaway segment 67, a leaf spring 69 isdisposed in frictional engagement with the periphery of the control disc60, said leaf spring being carried by a pin 70 pressed into a suitableaperture in the partition 28 and depending therefrom.

To place the control device into operation, the knob 51 is first presseddownwardly to thereby move the shaft 31 and casing members 36 and 39,together with the mechanism therein, downwardly against the bias of thespring 43. This downward movement of the shaft 31 effects downwardopening movement of the valve member 23 against the bias of the spring25, and said downward movement also moves the control disc 60 downwardlybelow the lower end of the pin 66 as shown in FIGURE 2. With the partsthus depressed, the knob 51 is rotated clockwise to any desired settingabove the minimum time setting which is indicated as one hour for theillustrated device. Such clockwise knob rotation effects immediaterotation of the shaft 31 therewith in a clockwise direction, and suchshaft rotation winds up the timer mechanism 35. As the shaft 31 rotatesclockwise, the pin 68 swings in a clockwise direction in the cutawaysector 67 of hub 62, and just before the knob 51 reaches thepredetermined minimum time setting, the pin 68 moves into abutment withthe cutaway sector end wall 67a, so that further clockwise rotation ofthe shaft 31 with the knob 51 causes clockwise movement of the controldisc 60 therewith and movement of the escapement or cutaway portion 65out of registration with the depending pin 66. Thus no clockwiserotation will be imparted to the disc 60 in response to clockwiserotation of the knob 51 until said knob has been moved beyond thepredetermined minimum setting.

Upon release of the knob 51, the parts remain in the depressed positiondue to the fact that the escapement portion 65 of the control disc 60has been rotated out of registration with the depending pin 66.Immediately upon release of the knob 51, the timer mechanism 35 beginsto return the shaft 31 in a counterclockwise direction at a timed rate.It will be observed, however, that no counterclockwise rotation isimparted to the control disc 60 until the pin 68 has been rotated fromits position in contact with the end wall 67a of sector 67 intoengagement with the opposite end wall 67b of said sector. Since the timerequired for movement of the pin 68 from engagement with one end wall tothe other of the sector 67 is the predetermined minimum time on periodfor the device, it will be observed that no counterclockwise rotation ofthe control disc 60 can be eifected by counterclockwise rotation of theshaft 31 until the predetermined minimum time on period has elapsed.

The lost-motion connection between the fitting 47 and and pin 46provided by the cutaway sector 53 prevents counterclockwise rotation ofthe shaft 31 by manual ac tuation of the knob 51 until there has beencounterclockwise rotation of the knob 51 sufficient to bring the endwall 53b of cutaway sector 53 into engagement with the pin 46. However,since the knob 51 is prevented by pins 58 and 59 from being rotated in acounterclockwise direction beyond its initial or off position, the shaft31 cannot be rotated manually in a counterclockwise direction to aposition corresponding to less than the pre determined minimum time onsetting. The spring 56 functions to cause the knob 51 to maintain theaforementioned predetermined relationship with the shaft 31, so thatsaid knob rotates with said shaft in a counterclockwise direction withthe passage of time and indicates on the dial 57 the length of time thedevice will subsequently remain on, i.e., the valve member 23 will beheld open. As the shaft 31 and knob 51 approach their initial positionsof rotation, the control disc 60 likewise approaches its initialposition of rotation, and as the escapement portion 65 moves intoregistration with the pin 66 the spring 43 biases the depressed assemblyupwardly, and the spring 25 biases the valve 23 to closed position inwhich it remains until the knob 51 is reset to initiate anotheroperative cycle.

It is apparent that the improved device cannot be set into operationunless the knob 51 is rotated at least to the predetermined minimum timeon setting. It is also apparent that the improved device has embodiedtherein non-frustratable means for preventing turndown of the device,once set to open position, to a setting less than the predeterminedminimum time on setting prescribed by the manufacturer.

Having described the invention as embodied in one specific fuel controlvalve structure and organization, it is to be expressly understood thatthe illustrated form of the invention was selected to facilitate thedisclosure and is not intended to impose any unnecessary limitations onthe claims or to confine the invention to a particular use. Variouschanges and modifications may be made in the disclosed embodiment tomeet the requirements of practice, without in any manner departing fromthe spirit of the invention, and all of such changes are contemplated asmay come within the scope of the appended claims.

What is claimed as the invention is:

1. In combination, a manually rotatable knob having an initial positionand rotatable therefrom in one direction through a predetermined angle,a shaft rotatable from an initial position through said predeterminedangle, a first lost-motion connection between said knob and shaftoperative upon rotation of said knob in one direction to correspondinglyrotate said shaft, the lost motion of said connection preventingsubsequent reverse actuation of said shaft [by reverse rotation of saidknob until said knob has been rotated through a predetermined minimumangle in said reverse direction, a control member rotatable from aninitial position through a predetermined angle, and a secondlost-rnotion connection between said shaft and said control memberoperable only after rotation of said shaft through a predeterminedminimum angle from its initial position to rotate said control membertherewith from its initial position.

2. In combination, a manually rotatable knob having an initial positionand rotatable therefrom in one direction through a predetermined angle,means preventing rotation of said knob in the opposite direction fromsaid initial position, a shaft rotatable from an initial positionthrough said predetermined angle, a first lost-motion connection betweensaid knob and shaft operative upon rotation of said knob in onedirection to correspondingly rotate said shaft, the lost motion of saidconnection preventing subsequent reverse actuation of said shaft byreverse rotation of said knob until said knob has been rotated through apredetermined minimum angle in said reverse direction, a control memberrotatable from an initial position through a predetermined angle, and asecond lost-motion connection between said shaft and said control mmeberoperable only after rotation of said shaft through a predeterminedminimum angle from its initial position to rotate said control membertherewith from its initial position.

3. In combination, a manually rotatable knob having an initial positionand rotatable therefrom in one direction through a predetermined angle,a shaft rotatable from an initial position through said predeterminedangle, a spring loaded first lost-motion connection between said knoband shaft operative upon rotation of said knob in one direction tocorrespondingly rotate said shaft, the lost motion of said connectionpreventing subsequent reverse actuation of said shaft by reverserotation of said knob until said knob has been rotated through apredetermined minimum angle in said reverse direction, a control memberrotatable from an initial position through a predetermined angle, and asecond lost-motion connection between said shaft and said control memberoperable only after rotation of said shaft through a predeterminedminimum angle from its initial position to rotate said control membertherewith from its initial position.

4. In combination, a manually rotatable knob having an initial positionand rotatable therefrom in one direction through a predetermined angle,means preventing rotation of said knob in the opposite direction fromsaid initial position, a shaft rotatable from an initial positionthrough said predetermined angle, a first lost-motion connection betweensaid knob and shaft operative upon rotation of said knob in onedirection to correspondingly rotate said shaft, the lost motion of saidconnection preventing subsequent reverse actuation of said shaft byreverse rotation of said knob until said knob has been rotated through apredetermined minimum angle in said reverse direction, a control memberrotatable from an initial position through a predetermined angle, asecond lost-motion connection between said shaft and said control memberoperable only after rotation of said shaft through a predeterminedminimum angle from its initial position to rotate said control membertherewith from its initial position, and means tending to return saidshaft toward its initial position, the lost motion in said secondlost-motion connection preventing reverse actuation of said controlmember by return movement of said shaft until said shaft has rotatedthrough said last-mentioned minimum angle in said reverse direction.

5. In combination, a manually rotatable knob having an initial positionand rotatable therefrom in one direction through a predetermined angle,means preventing rotation of said knob in the opposite direction fromsaid initial position, an axially movable shaft rotatable from aninitial position through said predetermined angle, a first lost-motionconnection between said knob and shaft operative upon rotation of saidknob in one direction to correspondingly rotate said shaft, the lostmotion of said connection preventing subsequent reverse actuation ofsaid shaft by reverse rotation of said knob until said knob has beenrotated through a predetermined minimum angle in said reverse direction,a control member rotatable from an initial position through apredetermined angle, a second lost-motion connection between said shaftand said control member operable only after rotation of said shaftthrough a predetermined minimum angle from its initial position torotate said control member therewith from its initial position, meansfor moving said control member from its initial position axially withsaid shaft, and means for preventing substantial axial movement of saidcontrol member and shaft except when said control member is in itsinitial position of rotation and for preventing rotation of said controlmember except when the: latter is moved axially from its initialposition a predetermined distance.

6. In combination, a manually rotatable knob having an initial positionand rotatable therefrom in one direction through a predetermined angle,means preventing rotation of said knob in the opposite direction fromsaid initial position, an axially movable shaft rotatable from aninitial position through said predetermined angle, a first lost-motionconnection between said knob and shaft operative upon rotation of saidknob in one direction to correspondingly rotate said shaft, the lostmotion of said connection preventing subsequent reverse actuation ofsaid shaft by reverse rotation of said knob until said knob has beenrotated through a predetermined minimum angle in said reverse direction,a control member rotatable from an initial position through apredetermined angle, a second lost-motion connection between said shaftand said control member operable only after rotation of said shaftthrough a predetermined minimum angle from its initial position torotate said control member therewith from its initial position, meansfor moving said control member from its initial position axially withsaid shaft, means for preventing substantial axial movement of saidcontrol member and shaft except when said control member is in itsinitial position of rotation and for preventing rotation of said controlmember except when the latter is moved axially from its initial positiona predetermined distance, and a flow control member operatively relatedto said shaft and movable from one controlling position to another withaxial movement of said shaft.

7. In combination, a manually rotatable knob having an initial positionand rotatable therefrom in one direction through a predetermined angle,means preventing rotation of said knob in the opposite direction fromsaid initial position, an axially movable shaft rotatable from aninitial position through said predetermined angle, a first lost-motionconnection between said knob and shaft operative upon rotation of saidknob in one direction to correspondingly rotate said shaft, the lostmotion of said connection preventing subsequent reverse actuation ofsaid shaft by reverse rotation of said knob until said knob has beenrotated through a predetermined minimum angle in said reverse direction,rotary biasing means tending to return said shaft to its initialposition of rotation when rotated therefrom in said one direction, acontrol member rotatable from an initial position through :apredetermined angle, a second lost-motion connection between said shaftand said control member operable only after rotation of said shaftthrough a predetermined minimum angle from its initial position torotate said control member therewith from its initial position, meansfor moving said control member from its initial position axially withsaid shaft, and means for preventing substantial axial movement of saidcontrol member and shaft except when said control member is in itsinitial position of rotation and for preventing rotation of said controlmember except when the latter is moved axially from its initial positiona pre-- determined distance, the lost motion in said second lostmotionconnection preventing reverse actuation of said control member by returnmovement of said shaft until said shaft has rotated in said returndirection through said predetermined angle of said second connection.

8. In combination, a manually rotatable knob having an initial positionand rotatable therefrom in one direction through a predetermined angle,means preventing rotation of said knob in the opposite direction fromsaid initial position, an axially movable shaft rotatable from aninitial position through said predetermined angle, a first lostmotionconnection between said knob and shaft operative upon rotation of saidknob in one direction to correspondingly rotate said shaft, the lostmotion of said connection preventing subsequent reverse actuation ofsaid shaft by reverse rotation of said knob until said knob has beenrotated through a predetermined minimum angle in said reverse direction,rotary biasing means tending to return said shaft to its initialposition of rotation when rotated therefrom in said one direction, axialbiasing means tending to return said shaft axially to its initialposition when depressed axially therefrom, a control member rotatablefrom an initial position through a predetermined angle, a secondlost-motion connection between said shaft and said control memberoperable only after rotation of said shaft through a predeterminedminimum angle from its initial position to rotate said control membertherewith from its initial position, means for moving said controlmember from its initial position axially With said shaft, means forpreventing substantial axial movement of said control member and shaftexcept when said control member is in its initial position of rotationand for preventing rotation of said control member except when thelatter is depressed axially with said shaft from its initial position apredetermined distance, the lost motion in said second lost-motionconnection preventing reverse actuation of said control member by returnmovement of said shaft until said shaft has rotated in said returndirection through said predetermined angle of said second connection,and a valve member operatively related to said shaft and movable fromclosed to open position by depression of said shaft axially from itsinitial position.

9. An incinerator control or the like having a nonfrustratablepredetermined minimum time operational cycle, comprising a shaft mountedfor axial and rotative movement, means biasing said shaft in one axialdirection toward an initial position, a valve member operativelyassociated with said shaft and having means biasing the same towardclosed position, said valve being depressable toward open position byaxial depression of said shaft against the bias of its biasing means, acontrol disc having an escapement portion mounted on said shaft foraxial movement therewith and having a lost-motion rotary drivingconnection therewith, a fixedly mounted pin cooperable with said discand disposed in the escapement portion thereof when the latter and saidshaft are in their initial positions, said pin being operable to holdsaid disc and hence said shaft and valve in depressed position when saiddisc is depressed and rotated in one direction to move said escapementportion out of registry with said pin, a timer operatively associatedwith said shaft and tending to effect return rotation of the lattertoward its initial position at a timed rate following rotation of saidshaft in said one direction, a knob having a spring loaded rotarylost-motion connection with said shaft and operable when rotated in saidone direction from its initial position to rotate said shaft therewithin said one direction, said knob being movable axially with said shaft,and means for preventing reverse rotation of said knob beyond itsinitial position, the lost-motion connection of said shaft and controldisc preventing rotary actuation of said disc in response to rotation ofsaid knob from its initial position until said knob has been rotatedbeyond a predetermined minimum time setting of said timer, saidlast-mentioned lost-motion connection preventing reverse rotaryactuation of said disc by reverse rotation of said shaft until saidtimer has returned said shaft and knob through the angle correspondingto said predetermined timer setting, and the lost-motion connectionbetween said knob and shaft preventing reverse actuation of said shaftby reverse rotation of said knob until said knob has been rotated withrespect to said shaft toward its initial position through the anglecorresponding to said predetermined minimum timer setting.

10. In an incinerator control or the like, a knob having an initialposition and being manually movable therefrom in one direction, stopmeans preventing movement of said knob in the reverse direction fromsaid initial position, a movable shaft having an initial position, afirst lost motion connection between said knob and shaft operative uponmovement of said knob in said one direction to correspondingly move saidshaft, a timer tending to return said shaft toward its initial positionat a predetermined rate, the lost motion in said first connectionpreventing subsequent reverse actuation of said shaft by actuation ofsaid knob in said reverse direction until said knob has been moved apredetermined minimum amount in said reverse direction, a control membermovable from an initial toward a second controlling position, and asecond lost-motion connection between said shaft and said control memberoperable only after movement of said shaft a predetermined minimumamount from its initial position to move said control member therewithfrom its initail position.

11. In an incinerator control or the like, a knob having an initialposition and being manually rotatable therefrom in one direction, stopmeans preventing rotation of said knob in the reverse direction fromsaid initial position, a rotatable shaft having an initial position, afirst lost motion connection between said knob and shaft operative uponrotation of said knob in said one direction to correspondingly rotatesaid shaft, a timer tending to return said shaft toward its initialposition at a predetermined rate, the lost motion in said firstconnection preventing subsequent reverse rotation of said shaft byrotation of said knob in said reverse direction until said knob has beenrotated at predetermined minimum amount in said reverse direction, acontrol member movable from an initial toward a second controllingposition, and a second lost-motion connection between said shaft andsaid control member operable only after rotation of said shaft apredetermined minimum amount from its initial position to move saidcontrol member therewith from its initial position.

References Cited in the file of this patent UNITED STATES PATENTS1,993,926 Gauger Mar. 12, 1935 2,259,188 Whitehead Oct. 14, 19412,606,609 Johnson Aug. 12, 1952 2,653,659 Bloom Sept. 29, 1953

